This invention broadly relates to a fire-protection glass product which has a heat shielding characteristic and which is used so as to secure a safe escape route upon occurrence of fire and to prevent spread of fire towards an adjacent room.
As a product called a fire-protection glass, a wire glass, a tempered glass, and a crystallized glass are known and already commercially available. Such fire-protection glass has a heat resistance and not only can shield flames and smokes upon occurrence of fire but also serves as a window for securing an inside view. However, the above-mentioned fire-protection glass almost entirely transmits heat rays. This makes it difficult to secure a safe escape route and causes the spread of fire towards a next adjacent room.
In order to solve the above-mentioned problems, proposal has been made of a fire-protection glass product 12 illustrated in FIG. 1. Specifically, the fire-protection glass product 12 has a multilayer structure comprising two glass plates 10 with a gel layer 11 interposed therebetween. For example, such fire-protection glass product is disclosed in Japanese Unexamined Patent Publication No. Hei. 5-238782. The fire-protection glass product 12 has a heat shielding characteristic because, upon occurrence of fire, the gel layer 5 foams, i.e., produces bubbles to become clouded so that the heat rays can not be transmitted through the fire-protection glass product 12. In addition, the fire-protection glass product 12 has a heat insulating characteristic because an air layer is formed by the above-mentioned foaming.
Proposal has also been made of a fire-protection glass product 15 illustrated in FIG. 2. The fire-protection glass product 15 having a heat shielding characteristic comprises two glass plates 10 laminated via an intermediate resin layer 13 interposed therebetween with a heat ray reflection film 14 formed on one of the glass plates 10. For example, the fire-protection glass product 15 is disclosed in Japanese Unexamined Patent Publication No. 2001-97747.
The fire-protection glass product 15 utilizes infrared ray reflection function of carrier electrons of the heat ray reflection film 14 as well as infrared ray absorption function achieved by carbonization of the intermediate resin layer 13. Specifically, when an atmospheric temperature reaches a range between 800 and 900° C. upon occurrence of fire, the heat ray reflection film 14 is oxidized to reduce the carrier electrons and, therefore, can not sufficiently reflect the heat rays. So as to compensate such insufficient reflection by the heat ray reflection film 14, the intermediate resin layer 13 is carbonized following the temperature rise to absorb the heat rays. Thus, the transmission of the heat rays can be avoided.
However, the above-mentioned fire-protection glass product 12 having the gel layer 11 is high in material cost and heavy in weight so that the installation is difficult. In the fire-protection glass product 12 having the gel layer 11, the gel layer 11 becomes opaque in several minutes upon occurrence of fire. It is therefore difficult to monitor the condition of fire so that life saving and fire fighting are prevented or inhibited.
On the other hand, the fire-protection glass product 15 having the above-mentioned laminated glass structure and the heat ray reflection film 14 is high in material cost because of the laminated glass structure. Further, the intermediate resin layer 12 starts to be carbonized by heat in about 15 minutes upon occurrence of fire. As a consequence, it is difficult to monitor the condition of fire. This prevents life saving and fire fighting.